An electrophotographic color copier, commercially available as the Xerox 6500 color copier, adapted to produce a series of electrostatic latent images corresponding to a particular color component of an original, usually to be developed by a toner corresponding to the same color of the original, to provide a composite full color reproduction of the original is basically described in Davidson U.S. Pat. Nos. 3,906,897 and 3,934,549 and Sheikh U.S. Pat. No. 3,936,182. In such a system each partial color electrostatic latent image is developed typically with toner particles corresponding in color to the partial color image of the original. Typically three separate, color separated exposures and developements are made for example of the colors magenta, yellow and cyan and then the color separated toner images are transferred sequentially in registration to a sheet of paper to form a full color reproduction of the original.
Using such an electrophotographic color copier to make a color print of a color transparency is described in Mailloux U.S. Pat. No. 4,027,962. Cherian U.S. Pat. No. 4,014,607 describes apparatus for conveniently exposing either from a color transparency or an opaque original.
Bestenreiner et al. U.S. Pat. No. 3,780,214 describes scanning color originals point by point or line by line by electro-optical means to generate several sets of signals, each of which is used to regulate a laser beam in accordance with the distribution of a different color in the original. The laser beam exposures form thermal images representative of correspondingly colored portions of the original which may be superimposed over each other and transferred to a strip of paper to form a full color superimposed image.
A laser printer which includes a galvanometer for deflecting a modulated laser beam across a photoreceptive layer of an electrophotographic copier producing a visible image of the input signal is described in Mason Canadian Pat. No. 1,003,483.
IBM Belgian Pat. No. 846,804 published 1/17/77 and Starkweather U.S. Pat. No. 4,027,961 describe electrophotographic apparatus with a projection exposure station and a data-controlled light beam scan-printing station.
However none of the above patents discloses the preferred system of this invention which includes a relatively inexpensive, simple and compact data controlled laser scan apparatus adapted to be fitted e.g., as an accessory to existing commercially available electrophotographic copiers and preferably electrophotographic color copiers with a minimum of effort.